Electrochemical cells have been created utilizing various forms of gas electrodes. A gas electrode is an electrode that utilizes a gas, such as oxygen, as an active material and is capable of reducing the gas at the electrode, or an electrode that produces a gas via an oxidation reaction at the gas electrode, see for example U.S. Pat. Nos. 5,242,565; 5,707,499 and 6,060,196, which are hereby incorporated by reference. Gas electrodes have been used in metal-air cells, fuel cells, oxygen generating cells and hydrogen generating cells, for example.
Gas electrode containing electrochemical cells such as metal-air cells are desirable for use in many applications including electronic devices, such as hearing aids, sensors, computers, calculators, and watches. For example, oxygen sensors utilizing metal-air cells such as zinc air cells are disclosed in U.S. Pat. Nos. 5,902,467 and 6,758,962, which are hereby incorporated by reference. Metal-air cells are desirable for use in devices as they offer relatively high energy density or output per volume as oxygen from air outside the cell can be utilized by the cell as the active material of a positive electrode (cathode), when compared to electrochemical cells wherein the entire charge of both the negative electrode (anode) active material and positive electrode active material are contained inside a sealed cell container.
Thin, relatively flat electrochemical cells have been proposed, wherein various layers have been applied to a substrate to form a portion of the cell. Various techniques have been utilized to form thin cells. With the continued miniaturization of technology, there is an ever increasing desire to make batteries thinner.
U.S. Pat. Nos. 7,066,976; 6,967,183; 6,911,412; 6,881,511 and 6,280,871, assigned or co-assigned on their faces to Cabot Corporation, and which are hereby incorporated by reference, relate to composite electrocatalyst powders reportedly useful in energy devices, such as batteries and fuel cells. The electrocatalyst powders are formed into a layer, often in combination with other materials as part of a device such as a fuel cell or battery. The method by which these materials are deposited reportedly has a strong influence on the characteristics of the deposited layer, which in turn reportedly has a strong influence on the performance of the device.
U.S. Pat. No. 6,379,835, which is hereby incorporated by reference and is assigned on its face to Morgan Adhesives Company, relates to a flexible thin film battery including a film layer and a porous cathode deposited on a portion of a film and a porous anode deposited on a portion of the film, with an electrolyte and separator layer positioned between the porous anode and the porous cathode. The electrolyte is preferably dried so the battery is activated when liquid contacts the electrolyte and separator layer. In a preferred embodiment, water swellable particles are included in the cell. The film layers are at least partially sealed around the edges, confining the anode, cathode, and electrolyte and separator layer. The method of producing such a battery preferably includes printing various inks in a pattern on a polymeric film.
U.S. Pat. Nos. 6,030,721; 6,004,359; 5,865,859 and 5,747,191, which are hereby incorporated by reference and are assigned to Micron Communications, Inc. on their faces, relate to, in one aspect, a method of making a battery includes fusing an alkali metal onto a patterned conductive layer. In another aspect, a method of forming a battery includes: a) providing a cathode base which comprises: a first nonconductive surface; a first conductive layer superjacent the first nonconductive surface; the first conductive layer comprising a first area; and a cathode layer superjacent the first conductive layer leaving at least a portion of the first area exposed; b) providing an anode base which comprises: a second nonconductive surface; a second conductive layer superjacent the first nonconductive surface, the second conductive layer comprising a second area; and an anode layer superjacent the second conductive layer leaving at least a portion of the second area exposed, the anode layer comprising an alkali metal; and c) aligning and coupling the anode layer of the anode base with the cathode layer of the cathode base, wherein the aligning and coupling leaves at least a portion of the first area and at least a portion of the second area exposed for electrical connection. The invention also encompasses batteries formed by such methods. In another aspect, it is directed to batteries having a nonconductive layer next to a conductive layer wherein the conductive layer comprises a cured conductive ink. The cathode is against the conductive ink layer.
U.S. Patent Application Publication Nos. 2006/0115717 and 2003/0165744, assigned to Eveready Battery Co., Inc., and which are hereby incorporated by reference, relate to a flat, flexible electrochemical cell and describe various aspects of the flat, flexible electrochemical cell. A printed anode is provided that obviates the need for a discrete anode current collector, thereby reducing the size of the battery. An advantageous electrolyte is provided that enables the use of a metallic cathode current collector, thereby improving the performance of the battery. Printable gelled electrolytes and separators are provided, enabling the construction of both co-facial and co-planar batteries. Cell contacts are provided that reduce the potential for electrolyte creepage in the flat, flexible electrochemical cells of the within invention.
U.S. Patent Application Publication No. 2005/0260492 to Tucholski et al., and which is hereby incorporated by reference, relates to a thin printed flexible electrochemical cell with a high moisture and oxygen barrier polymer film sealed and folded package featuring a printed cathode deposited on a highly conductive carbon printed cathode collector with a zinc foil anode or printed anode placed adjacent to the cathode. After the cell components are added to the special laminated polymer substrate, the web is processed automatically on a modified high-speed commercial horizontal pouch filling machine to complete the cell assembly process. In this process a starch coated paper separator layer may be inserted over the anode and the cathode, and then the aqueous electrolyte solution is added to the cell. To complete the process, all four edges of the cell are heat sealed to confine the cell components within the cell cavity and each cell is trimmed off the continuous web.
In view of the above, it would be desirable to provide a relatively thin film electrochemical cell, including a gas electrode that is versatile and can be mass produced by a process comprising one or more deposition steps.